The present invention relates to a composition, in particular a cosmetic composition, comprising, in a physiologically acceptable medium, at least one polymer with a highly specific ordered structure. These compositions find a specific application in the field of caring for or making up keratinous fibres, in particular as a mascara composition for the eyelashes or for the hair.
It is common practice to produce mascara compositions comprising at least one wax. However, the wax is never used alone because make-up with such compositions proves to be very mediocre, leading to the formation, on the eyelashes, of a non-homogeneous film which is reflected by the formation of thin films which crack immediately after drying.
It is also known, for example according to Applications WO 96/36323 and WO 96/33690, to combine a wax and a film-forming polymer in a mascara composition. However, such a combination does not make it possible to give good curling to the eyelashes or to obtain a thick make-up on the eyelashes.
Mascara compositions comprising microdispersions of waxes in combination with film-forming polymers have also been provided, for example in Applications EP-A-557,196 and EP-A-639,371. However, such compositions do not make it possible to obtain a thick make-up on the eyelashes, these mascaras not having a high load.
The Inventor has found that, surprisingly and unexpectedly, the use of highly specific polymers exhibiting a specific ordered structure can make it possible to obtain a composition capable of being applied to keratinous fibres, in particular the eyelashes, which can make possible improved curling of the eyelashes, the curling furthermore being instantaneous and long-lasting.
Thus, a subject-matter of the present invention is a polymer with a xe2x80x9cstarxe2x80x9d structure represented by the following formula (I):
A-[(M1)p1-(M2)p2 . . . (Mi)pj]n 
in which:
A represents a polyfunctional centre, with a functionality of xe2x80x9cnxe2x80x9d, n being an integer greater than or equal to 2,
[(M1)p1-(M2)p2 . . . (Mi)pj] represents a polymer chain, also known as a xe2x80x9cbranchxe2x80x9d, composed of identical or different polymerized monomers Mi having a polymerization index pj, each branch being identical or different and being grafted covalently to the centre A;
i being greater than or equal to 1 and pj being greater than or equal to 2;
the polymer comprising one or more monomers Mi chosen from polymerized monomeric units Mk, which may be identical or different, wherein a homopolymer formed by the corresponding polymerized monomers Mk has a Tg of greater than or equal to approximately 10xc2x0 C., preferably of greater than or equal to 15xc2x0 C. and even better still of greater than or equal to 20xc2x0 C.
In a preferred embodiment, this or these monomers Mi being present, in the final polymer, in a minimum amount of approximately 45% by weight, preferably in an amount of between 55 and 99% by weight and even better still in an amount of 75-95% by weight with respect to the total weight of monomers.
Another subject-matter of the present invention is a polymer as described above further comprising one or more monomers Mj, the corresponding homopolymer of which exhibits a Tg of less than or equal to approximately 10xc2x0 C., preferably of less than or equal to 5xc2x0 C. and even better still of less than or equal to 0xc2x0 C.
In a preferred embodiment, this or these monomers Mj are present in the final polymer in a maximum amount of approximately 55% by weight, preferably in an amount of between 1 and 45% by weight and even better still in an amount of 5-25% by weight with respect to the total weight of monomers.
Another subject-matter of the invention is a composition comprising, in a physiologically acceptable medium, at least one polymer as defined above.
Another subject-matter of the invention is a process for the cosmetic treatment of keratinous fibres, in particular the eyelashes and/or hair, characterized in that it comprises applying, to the latter, a cosmetic composition as defined above.
Another subject-matter of the invention is the use of at least one polymer as defined above in a cosmetic composition to be applied to the eyelashes, for allowing improved curling of the eyelashes to be obtained.
The compositions according to the invention exhibit a light texture and are very comfortable to wear throughout the day. They adhere well to the substrate to which they are applied.
They exhibit good resistance to water and can be easily removed, for example using a conventional make-up remover, in particular one with an oily base.
The composition according to the invention therefore comprises a polymer, the xe2x80x9cstarxe2x80x9d structure of which can be illustrated, in a general way, by the following formula (I):
A-[(M1)p1-(M2)p2 . . . (Mi)pj]n 
in which:
A represents a polyfunctional centre, with a functionality of xe2x80x9cnxe2x80x9d, n being an integer greater than or equal to 2, preferably of between 4 and 10,
[(M1)p1-(M2)p2 . . . (Mi)pj] represents a polymeric chain, also known as a xe2x80x9cbranchxe2x80x9d, composed of identical or different polymerized monomers Mi having a polymerization index pj, each branch being identical or different and being grafted covalently to the centre A;
i being greater than or equal to 1, preferably of between 2 and 10;
pj being greater than or equal to 2, preferably of between 10 and 20,000.
The polymer chains are preferably provided in the form of blocks with a molecular mass of greater than or equal to 500 which can range up to 2,000,000.
In a preferred embodiment, the polymer used in the context of the present invention can be obtained by controlled radical polymerization, also known as xe2x80x9clivingxe2x80x9d radical polymerization. This technique makes it possible in particular to overcome the limitations inherent in conventional radical polymerization, that is to say that it makes it possible in particular to control the length of the chains of the polymer which is formed and therefore to obtain block structures.
The controlled radical polymerization makes it possible to reduce the reactions in which the growing radical species is deactivated, in particular the termination stage, which reactions, in conventional radical polymerization, interrupt the growth of the polymer chain in an irreversible and uncontrolled way.
In order to decrease the probability of termination reactions, provision has been made to block, in a temporary and reversible way, the growing radical species by forming so-called xe2x80x9cdormantxe2x80x9d active species with the aid of a bond of low dissociation energy.
In particular, mention may be made of the possibility of using bonds of Cxe2x80x94ONR type (by reaction with a nitroxyl); this is illustrated in particular by the article xe2x80x9cSynthesis of nitroxy-functionalized polybutadiene by anionic polymerization using a nitroxy-functionalized terminatorxe2x80x9d, published in Macromolecules, 1997, volume 30, pp. 4238-4242.
Mention may also be made of the possibility of using bonds of C-halide type (in the presence of metal/ligand complex). This is then described as atom transfer radical polymerization, also known under the abbreviation ATRP. This type of polymerization is reflected in control of the mass of the polymers which are formed and in a low polydispersity index by weight of the chains.
Atom transfer radical polymerization is generally carried out by polymerization:
of one or more radically polymerizable monomers, in the presence
of an initiator having at least one radically transferable atom or group,
of a compound comprising a transition metal capable of participating in a reduction stage with the initiator and a xe2x80x9cdormantxe2x80x9d polymer chain, and
of a ligand, which can be chosen from compounds comprising a nitrogen (N), oxygen (O), phosphorus (P) or sulphur (S) atom, which compounds are capable of coordinating via a "sgr" bond to the compound comprising a transition metal, or from compounds comprising a carbon atom, which compounds are capable of coordinating via a xcfx80 or "sgr" bond to the compound comprising a transition metal, the formation of direct bonds between the compound comprising a transition metal and the polymer in the course of formation being avoided.
This process is illustrated in particular in Application WO97/18247, the teaching of which can be drawn upon by a person skilled in the art in preparing the polymers coming within the scope of the present invention.
The nature and the amount of the monomers, initiator(s), compound(s) comprising the transition metal and ligand(s) will be chosen by a person skilled in the art on the basis of his overall knowledge, according to the result desired.
In particular, the monomers xe2x80x9cMxe2x80x9d (Mi, Mk, and Mj) can be chosen, alone or as a mixture, from radically polymerizable compounds comprising ethylenic unsaturation corresponding to the formula: 
in which R1, R2, R3 and R4 are, independently of one another, chosen from:
a hydrogen atom;
a halogen atom;
a linear or branched alkyl radical having 1 to 20, preferably 1-6, more preferably 1-4, carbon atoms which is optionally substituted by one or more halogens and/or one or more xe2x80x94OH radicals;
a linear or branched alkenyl or alkynyl radical having 2 to 10, preferably 2-6, more preferably 2-4, carbon atoms which is optionally substituted by one or more halogens;
a cyclic hydrocarbonaceous (cycloalkyl) radical having 3 to 8 carbon atoms which is optionally substituted by one or more halogen, nitrogen, sulphur or oxygen atoms;
a radical chosen from CN, C(xe2x95x90Y)R5, C(xe2x95x90Y)NR6R7, YC(xe2x95x90Y)R5, cyclic NC(xe2x95x90Y)R5, SOR5, SO2R5, OSO2R5, NR8SO2R5, PR52, P(xe2x95x90Y)R52, YPR52, YP(xe2x95x90Y)R52, NR82, which can be quaternized with an additional R8 group, aryl and heterocyclyl, with:
Y represents O, S or NR8 (preferably O),
R5 represents a linear or branched alkyl, alkylthio or alkoxy radical having 1-20 carbon atoms; an OH radical; an OMxe2x80x2 radical with Mxe2x80x2=alkali metal; an aryloxy radical or a heterocyclyloxy radical;
R6 and R7 represent, independently of one another, H or a linear or branched alkyl radical having 1-20 carbon atoms; it being given that R6 and R7 can be joined to form an alkylene group having 2-7, preferably 2-5, carbon atoms;
R8 represents H, a linear or branched alkyl radical having 1-20 carbon atoms or an aryl radical;
a xe2x80x94COOR radical, in which R is a linear or branched alkyl radical having 1 to 20, preferably 1-6, carbon atoms which is optionally substituted by one or more halogens;
a xe2x80x94CONHRxe2x80x2 radical, in which Rxe2x80x2 is hydrogen or a saturated or unsaturated, linear or branched, hydrocarbonaceous radical having 1 to 20, preferably 1-6, carbon atoms which is optionally substituted by one or more halogens, nitrogens and/or oxygens;
an xe2x80x94OCORxe2x80x3 radical, in which Rxe2x80x3 is hydrogen or a saturated or unsaturated, linear or branched, hydrocarbonaceous radical having 1 to 20 carbon atoms which is optionally substituted by one or more halogens, nitrogens and/or oxygens;
a radical comprising at least one silicon atom and in particular radicals such as: an xe2x80x94R-siloxane radical, a xe2x80x94CONHR-siloxane radical, a xe2x80x94COOR-siloxane radical or an xe2x80x94OCOxe2x80x94R-siloxane radical, in which radicals R is a linear or branched alkyl, alkylthio, alkoxy, aryloxy or heterocycloxy radical having 1-20 carbon atoms.
The term xe2x80x9csiloxanexe2x80x9d is understood to mean a compound comprising (xe2x80x94SiRaRbOxe2x80x94)n units, in which units Ra and Rb can represent, independently of one another, a hydrogen; a halogen; a saturated or unsaturated, linear or branched, hydrocarbonaceous radical having 1 to 36 carbon atoms which is optionally substituted by one or more halogens, nitrogens and/or oxygens; or a cyclic hydrocarbonaceous radical having 1 to 20 carbon atoms; n being greater than or equal to 1.
For the purpose of this invention, the term xe2x80x9cindependent,xe2x80x9d when used to describe the relationship of radicals, atoms, substituents, functional groups, etc., means that each of the radicals, atoms, substituents, functional groups, etc. may be the same or different from the other, or some radicals, atoms, substituents functional groups, etc., may be the same while the others may be different.
Mention may in particular be made of polydimethylsiloxanes (PDMSs) comprising 1 to 200, preferably less than 100, repeat units.
Furthermore, R1 and R3 can be connected to one another so as to form a ring of formula (CH2)n which can be substituted by one or more halogens and/or oxygens and/or nitrogens and/or by alkyl radicals having 1 to 6 carbon atoms.
The term xe2x80x9carylxe2x80x9d or xe2x80x9cheterocyclylxe2x80x9d is understood to mean the definition commonly understood by a person skilled in the art and which may be illustrated by the prior art WO97/18247.
Preferably, the monomers M can be chosen from:
acrylic or methacrylic esters obtained from linear, branched or cyclic aliphatic alcohols and/or from aromatic alcohols, preferably C1-C20 alcohols, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate;
C1-C4 hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate;
ethylene glycol, diethylene glycol or polyethylene glycol (meth)acrylates with a hydroxyl or ether end;
vinyl, allyl or methallyl esters obtained from linear or branched C1-C10 or cyclic C1-C6 aliphatic alcohols and/or from aromatic alcohols, preferably C1-C6 alcohols, such as vinyl acetate, vinyl propionate, vinyl benzoate or vinyl tert-butylbenzoate;
N-vinylpyrrolidone; vinylcaprolactam; vinyl-N-alkylpyrroles having 1 to 6 carbon atoms; vinyloxazoles; vinylthiazoles; vinylpyrimidines; vinylimidazoles; and vinyl ketones;
(meth)acrylamides obtained from linear, branched or cyclic aliphatic amines and/or from aromatic amines, preferably C1-C20 amines, such as tert-butylacrylamide; and (meth)acrylamides, such as acrylamide, methacrylamide or di(C1-C4)alkyl(meth)acrylamides;
olefins, such as ethylene, propylene, styrene or substituted styrene;
fluorinated or perfluorinated acrylic or vinyl monomers, in particular (meth)acrylic esters with perfluoroalkyl units;
monomers comprising an amine functional group in the free or else partially or completely neutralized or else partially or completely quaternized form, such as dimethylaminoethyl (meth)acrylate, dimethylaminoethylmethacrylamide, vinylamine, vinylpyridine or diallyldimethylammonium chloride;
carboxybetaines or sulphobetaines obtained by partial or complete quaternization of monomers comprising ethylenic unsaturation comprising an amine functional group by sodium salts of carboxylic acids comprising a mobile halide (sodium chloroacetate, for example) or by cyclic sulphones (propane sulphone);
silicone-comprising (meth)acrylates or (meth)acrylamides, in particular (meth)acrylic esters comprising siloxane units;
their mixtures.
The particularly preferred monomers are chosen from:
(meth)acrylic esters obtained from linear or branched aliphatic alcohols, preferably C1-C20 alcohols;
C1-C20 (meth)acrylic esters comprising perfluoroalkyl units;
C1-C20 (meth)acrylic esters comprising siloxane units;
(meth)acrylamides obtained from linear, branched or cyclic aliphatic amines and/or from aromatic amines, preferably C1-C20 amines, such as tert-butylacrylamide; or (meth)acrylamides, such as acrylamide, methacrylamide or di(C1-C4)alkyl(meth)acrylamides;
vinyl, allyl or methallyl esters obtained from linear or branched C1-C10 or cyclic C1-C6 aliphatic alcohols;
vinylcaprolactam;
optionally substituted styrene;
their mixtures.
In the context of the present invention, the initiator can be any compound, in particular a molecular or polymeric compound, having at least two atoms and/or groups which are radically transferable by polymerization.
The initiator can in particular be an oligomer or a polymer capable of being obtained by radical polymerization, by polycondensation, by anionic or cationic polymerization or by ring opening.
The transferable atoms and/or groups can be situated at the ends of the polymer chain or along the backbone.
Mention may in particular be made of the compounds corresponding to one of the following formulae:
R11COxe2x80x94X
R11xR12yR13zCxe2x80x94(RX)t, in which x, y and z represent an integer ranging from 0 to 4, t an integer ranging from 1 to 4, and x+y+z=4xe2x88x92t;
R13xC6xe2x80x94(RX)y (saturated ring with 6 carbons), in which x represents an integer ranging from 7 to 11, y represents an integer ranging from 1 to 5, and x+y=12;
R13xC6xe2x80x94(RX)y (unsaturated ring with 6 carbons), in which x represents an integer ranging from 0 to 5, y represents an integer ranging from 1 to 6, and x+y=6;
xe2x80x94[xe2x80x94(R11)(R12)(R13)Cxe2x80x94(RX)xe2x80x94]n, in which n is greater than or equal to 1; cyclic or linear;
xe2x80x94[xe2x80x94(R12)xC6(RX)yxe2x80x94R11xe2x80x94]n, in which x represents an integer ranging from 0 to 6, y represents an integer ranging from 1 to 6 and n is greater than or equal to 1, with x+y=4 or 6; cyclic or linear;
xe2x80x94[xe2x80x94(R12)xC6(RX)yxe2x80x94R11xe2x80x94]n, in which x represents an integer ranging from 0 to 12, y represents an integer ranging from 1 to 12 and n is greater than or equal to 1, with x+y=10 or 12; cyclic or linear;
R11R12R13Sixe2x80x94X
xe2x80x94[OSi(R11)x(RX)y]n, cyclic or linear, in which x and y represent an integer ranging from 0 to 2 and n is greater than or equal to 1, with x+y=2;
R11R12Nxe2x80x94X
R11Nxe2x80x94X2 
(R11)xP(O)yxe2x80x94X3xe2x88x92x in which x and y represent integers ranging from 0 to 2 and x+y=5;
(R11O)xP(O)yxe2x80x94X3xe2x88x92x in which x and y represent integers ranging from 0 to 2 and x+y=5;
xe2x80x94[(R11)tNzP(O)x(Oxe2x80x94RX)yxe2x80x94]n, cyclic or linear, in which x represents an integer ranging from 0 to 4, y represents an integer ranging from 1 to 5, z represents an integer ranging from 0 to 2, t represents an integer ranging from 0 to 3 and n is greater than or equal to 1;
in which:
R, R11, R12 and R13 represent, independently of one another, a hydrogen or halogen atom; a linear or branched alkyl radical having 1-20, preferably 1-10 and more preferably 1-6 carbon atoms; a cycloalkyl radical having 3-8 carbon atoms; a xe2x80x94C(xe2x95x90Y)R5, xe2x80x94C(xe2x95x90Y)NR6R7 or xe2x80x94R83Si radical (see the definitions of R5 to R8 above); xe2x80x94COCl; xe2x80x94OH; xe2x80x94CN; an alkenyl or alkynyl radical having 2-20, preferably 2-6, carbon atoms; an oxiranyl or glycidyl radical or an alkylene or alkenylene radical substituted with an oxiranyl or a glycidyl; an aryl, heterocyclyl, aralkyl or aralkenyl radical; or an alkyl radical having 1-6 carbon atoms in which all or part of the hydrogen atoms are substituted either by halogen atoms, such as fluorine, chlorine or bromine, or by an alkoxy group having 14 carbon atoms or by an aryl, heterocyclyl, xe2x80x94C(xe2x95x90Y)R5, xe2x80x94C(xe2x95x90Y)NR6R7, oxiranyl or glycidyl radical;
X represents a halogen atom, such as Cl, Br or I, or an xe2x80x94ORxe2x80x2, xe2x80x94SR, xe2x80x94SeR, xe2x80x94OC(xe2x95x90O)Rxe2x80x2, xe2x80x94OP(xe2x95x90O)Rxe2x80x2, xe2x80x94OP(xe2x95x90O)(ORxe2x80x2)2, xe2x80x94OP(xe2x95x90O)ORxe2x80x2, xe2x80x94Oxe2x80x94NRxe2x80x22, xe2x80x94Sxe2x80x94C(xe2x95x90S)NRxe2x80x22, xe2x80x94CN, xe2x80x94NC, xe2x80x94SCN, xe2x80x94CNS, xe2x80x94OCN, xe2x80x94CNO and xe2x80x94N3 radical, in which Rxe2x80x2 represents an alkyl radical having 1-20 carbon atoms which is optionally substituted by one or more halogen atoms, in particular fluorine and/or chlorine atoms, and R represents a linear or branched alkyl or aryl radical having 1-20, preferably 1-10, carbon atoms, it additionally being possible for the xe2x80x94NRxe2x80x22 group to represent a cyclic group, the two Rxe2x80x2 groups being joined so as to form a 5-, 6- or 7-membered heterocycle.
Preferably, X represents a halogen atom and in particular a chlorine or bromine atom.
The initiator is preferably chosen from the compounds of formula
R13xC6xe2x80x94(RX)y (saturated ring with 6 carbons) in which x represents an integer ranging from 7 to 11, y represents an integer ranging from 1 to 5 and x+y=12;
xe2x80x94[xe2x80x94(R12)xC6(RX)yxe2x80x94R11xe2x80x94]n, in which x represent an integer ranging from 0 to 6, y represents an integer ranging from 1 to 6 and n is greater than or equal to 1, with x+y=4 or 6; cyclic or linear; and
xe2x80x94[OSi(R11)x(RX)y]n, cyclic or linear, in which x and y represent an integer ranging from 0 to 2 and n is greater than or equal to 1, with x+y=2.
Mention may in particular be made, as initiator, of the following compounds:
octa(2-isobutyrylbromide)octa(tert-butyl)calix(8)arene,
octa(2-propionylbromide)octa(tert-butyl)calix(8)arene, and
hexakis(xcex1-bromomethyl)benzene.
The compound comprising a transition metal which is capable of participating in a reduction stage with the initiator and a xe2x80x9cdormantxe2x80x9d polymer chain can be chosen from those which correspond to the formula Mn+Xxe2x80x2n, in which formula:
M can be chosen from Cu, Au, Ag, Hg, Ni, Pd, Pt, Rh, Co, Ir, Fe, Ru, Os, Re, Mn, Cr, Mo, W, V, Nb, Ta and Zn,
Xxe2x80x2 can represent a halogen (in particular bromine or chlorine), OH, (O)xc2xd, an alkoxy radical having 1-6 carbon atoms, (SO4)xc2xd, (PO4)⅓, (HPO4)xc2xd, (H2PO4), a triflate, hexafluorophosphate, methanesulphonate, arylsulphonate, SeR, CN, NC, SCN, CNS, OCN, CNO, N3 and Rxe2x80x2CO2 radical, in which R represents a linear or branched alkyl or aryl radical having 1-20, preferably 1-10, carbon atoms and Rxe2x80x2 represents H or a linear or branched alkyl radical having 1-6 carbon atoms or an aryl radical which is optionally substituted by one or more halogen atoms, in particular fluorine and/or chlorine atoms;
n is the charge on the metal.
The choice is preferably made of M representing copper or ruthenium and Xxe2x80x2 representing bromine or chlorine.
Mention may in particular be made of copper bromide.
Mention may be made, among the ligands capable of being used in the context of the present invention, of compounds comprising at least one nitrogen, oxygen, phosphorus and/or sulphur atom which are capable of coordinating via a "sgr" bond to the compound comprising a transition metal.
Mention may also be made of compounds comprising at least two carbon atoms which are capable of coordinating via a xcfx80 bond to the compound comprising a transition metal.
Mention may further be made of compounds comprising at least one carbon atom which are capable of coordinating via a "sgr" bond to the compound comprising a transition metal but which do not form a carbonxe2x80x94carbon bond with the monomer during the polymerization, that is to say which do not participate in xcex2-addition reactions with the monomers.
Mention may further be made of compounds capable of coordinating via xcexc or xcex7 bond to the compound comprising a transition metal.
Mention may in particular be made of the compounds of formula:
R9xe2x80x94Zxe2x80x94(R14xe2x80x94Z)mxe2x80x94R10 
in which:
R9 and R10 are, independently of one another, a hydrogen atom; a linear or branched alkyl radical having 1-20, preferably 1-10, carbon atoms; an aryl radical; a heterocyclyl radical; or an alkyl radical having 1-6 carbon atoms which is substituted with an alkoxy radical having 1-6 carbon atoms or a dialkylamino radical having 14 carbon atoms or a xe2x80x94C(xe2x95x90Y)R5 or xe2x80x94C(xe2x95x90Y)NR6R7 and/or YC(xe2x95x90Y)R8 radical (see the definitions R5 to R8 and Y above); it being given that R9 and R10 can be joined so as to form a saturated or unsaturated ring;
R14 represents, independently of one another, a divalent group chosen from alkanediyls having 24 carbon atoms; alkenylenes having 24 carbon atoms; cycloalkanediyls having 3-8 carbon atoms; cycloalkenediyls having 3-8 carbon atoms; arenediyls and heterocyclylenes;
Z represents O, S, NR15 or PR15, with R15 representing H; a linear or branched alkyl radical having 1-20 carbon atoms; an aryl radical; a heterocyclyl radical; or an alkyl radical having 1-6 carbon atoms which is substituted with an alkoxy radical having 1-6 carbon atoms or a dialkylamino radical having 14 carbon atoms or a xe2x80x94C(xe2x95x90Y)R5 or xe2x80x94C(xe2x95x90Y)NR6R7 and/or YC(xe2x95x90Y)R8 radical (see the definitions of R5 to R8 and Y above);
m is between 0 and 6.
Mention may also be made of the compounds of formula:
R20R21C[C(xe2x95x90Y)R5]
in which:
R20 and R21 are, independently of one another, a hydrogen atom; a halogen atom; a linear or branched alkyl radical having 1-20, preferably 1-10, carbon atoms; an aryl radical; or a heterocyclyl radical; it being given that R20 and R21 can be joined so as to form a saturated or unsaturated ring; it being given that, in addition, each radical can be substituted with an alkyl radical having 1-6 carbon atoms, an alkoxy radical having 1-6 carbon atoms or an aryl radical;
R5 and Y being defined above.
Mention may further be made, as ligands, of carbon monoxide; optionally substituted porphyrins and porphycenes; optionally substituted ethylenediamine and propylenediamine; polyamines with tertiary amines, such as pentamethyldiethylenetriamine; aminoalcohols, such as aminoethanol and aminopropanol, which are optionally substituted; glycols, such as ethylene glycol or propylene glycol, which are optionally substituted; arenes, such as benzene, which are optionally substituted; optionally substituted cyclopentadiene; optionally substituted pyridines and bipyridines; acetonitrile; 1,10-phenanthroline; cryptands and crown ethers; or sparteine.
The preferred ligands are chosen in particular from pyridines and bipyridines which are optionally substituted by C2-C15 alkyl radicals, in particular C6-C12 radicals and especially the nonyl radical; or polyamines with tertiary amines, such as pentamethyldiethylenetriamine.
The polymerization of the monomers, in the presence of the initiator, of the compound comprising a transition metal and of the ligand which acts as activator, results in the production of a polymer having a star structure, which can be represented by the formula (I) given above, in which the monomers have polymerized to give xe2x80x9cnxe2x80x9d alike or different polymer chains all connected to a polyfunctional centre A which derives from the initiator.
It has been found that, in order to achieve the goal pursued by the present invention, that is to say to obtain a composition which does not exhibit the disadvantages of the prior art and which in particular allows sufficient curling of the eyelashes to be obtained, it is preferable to choose a polymer corresponding to the following criteria:
it preferably comprises one or more monomers Mi, the corresponding homopolymer of which exhibits a Tg of greater than or equal to approximately 10xc2x0 C., preferably of greater than or equal to 15xc2x0 C. and even better still of greater than or equal to 20xc2x0 C.;
this or these monomers Mi being present in the final polymer in a minimum amount of approximately 45% by weight, preferably in an amount of between 55 and 99% by weight and even better still in an amount of 75-95% by weight with respect to the total weight of monomers.
The polymer may or may not comprise other monomers.
However, it is possible for it to additionally comprise one or more monomers Mj, the corresponding homopolymer of which exhibits a Tg of less than or equal to approximately 10xc2x0 C., preferably of less than or equal to 5xc2x0 C. and even better still of less than or equal to 0xc2x0 C.
In this case, this or these monomers Mj are present in the final polymer in a maximum amount of approximately 55% by weight, preferably in an amount of between 1 and 45% by weight and even better still in an amount of 5-25% by weight with respect to the total weight of monomers.
The Tg (glass transition temperature) is measured by DSC (Differential Scanning Calorimetry) according to ASTM Standard D3418-97.
The polymers as defined in the present invention are preferably be film-forming or can be rendered film-forming by addition of an additional agent which is able to form a film. The term xe2x80x9cfilm-formingxe2x80x9d is understood to mean that the polymer, after application to a substrate and evaporation of the solvent (aqueous or organic), results in a transparent and uncracked film.
Such an additional agent which is able to form a film can be chosen from any compound known to a person skilled in the art as being capable of fulfilling the desired role and can be chosen in particular from plasticizing agents and/or from coalescence agents. Mention may in particular be made, alone or as a mixture, of:
glycols and their derivatives, such as diethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol butyl ether, diethylene glycol hexyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether or ethylene glycol hexyl ether;
glycerol esters, such as glycerol diacetate (diacetin) and glycerol triacetate (triacetin);
propylene glycol derivatives, in particular propylene glycol phenyl ether, propylene glycol diacetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol butyl ether, dipropylene glycol ethyl ether, tripropylene glycol butyl ether or tripropylene glycol methyl ether;
acid esters, in particular carboxylic acid esters, such as citrates, phthalates, adipates, carbonates, tartrates, phosphates or sebacates,
oxyethylenated derivatives, such as oxyethylenated oils, in particular vegetable oils, such as castor oil; or oxyethylenated silicone oils.
The amount of additional agent which is able to form a film can be chosen by a person skilled in the art on the basis of his overall knowledge so as to form a film having the desired mechanical properties while retaining, in the composition, cosmetically acceptable properties.
In a preferred embodiment of the invention, a polymer, optionally in combination with additional agents which are able to form a film, is chosen which makes it possible to obtain a film having the following physicochemical characteristic:
a retraction of the isolated stratum corneum which is greater than approximately 1%, preferably greater than or equal to 1.1%, measured using a dermometer, at 30xc2x0 C., under a relative humidity of 40%, for a concentration of 7% of polymer in a solvent such as isododecane or water.
The polymers as defined above can be present in the medium in a form dissolved or dispersed in an aqueous, organic or aqueous/organic phase, in particular an alcoholic or aqueous/alcoholic phase.
The polymers can be present in the composition according to the invention in an amount which can be easily determined by a person skilled in the art according to the application envisaged and which can be between 1-99% by weight, on a dry basis, with respect to the total weight of the composition, preferably between 1.5-50% by weight and preferably between 2-30% by weight.
The compositions, in particular cosmetic compositions, according to the, invention therefore additionally comprise a physiologically acceptable medium which can be chosen by a person skilled in the art according to the application envisaged.
This medium can comprise an aqueous phase and/or a fatty phase. It can also be anhydrous.
The aqueous phase can comprise water and/or a thermal water and/or a spring water and/or a mineral water and/or a floral water.
It can also comprise one or more cosmetically acceptable organic solvents or else a mixture of water and of one or more cosmetically acceptable organic solvents. Mention may be made, among these organic solvents, of:
C1-C4 alcohols, such as ethanol, ispropanol or n-propanol;
ethers, such as dimethoxyethane;
ketones, such as acetone or methyl ethyl ketone;
lower C1-C3 carboxylic acid esters, such as methyl acetate or ethyl acetate.
The fatty phase can comprise conventional volatile or non-volatile oils, gums and/or waxes of animal, vegetable, mineral or synthetic origin, alone or as mixtures, in particular:
linear, branched or cyclic, volatile or non-volatile, silicone oils which are optionally organomodified; phenylated silicones; or silicone resins and gums which are liquid at room temperature;
mineral oils, such as liquid paraffin and liquid petrolatum;
oils of animal origin, such as perhydrosqualene or lanolin;
oils of vegetable origin, such as liquid triglycerides, for example sunflower, maize, soybean, jojoba, gourd, grape seed, sesame, hazlenut, apricot, macadamia, avocado, sweet almond or castor oils, triglycerides of caprylic/capric acids, olive oil, groundnut oil, rapeseed oil or coconut oil;
synthetic oils, such as purcellin oil, isoparaffins, fatty alcohols or esters of fatty acids;
fluorinated and perfluorinated oils or fluorinated silicone oils;
waxes chosen from known animal, fossil, vegetable, mineral or synthetic waxes, such as paraffin waxes, polyethylene waxes, carnauba or candelilla waxes, beeswaxes, lanolin wax, chinese insect waxes, rice wax, ouricury wax, esparto wax, cork fibre wax, sugarcane wax, japan wax, sumach wax, montan wax, microcrystalline waxes, ozokerite, the waxes obtained by the Fischer-Tropsch synthesis, silicone waxes or their mixtures.
The composition can additionally comprise at least one water-soluble dye and/or at least one pigment which are used conventionally in the field of cosmetics and make-up. The term xe2x80x9cpigmentsxe2x80x9d should be understood as meaning white or coloured and inorganic or organic particles which are insoluble in the medium and which are intended to colour and/or opacify the composition. The pigments can be present in the composition in a proportion of 0-20% by weight of the final composition and preferably in a proportion of 1-5%. They can be white or coloured, inorganic and/or organic and conventional or nanometric in size. Mention may be made, among inorganic pigments and nanopigments, of titanium, zirconium or cerium oxides, as well as zinc, iron or chromium oxides or ferric blue. Mention may be made, among organic pigments, of carbon black and barium, strontium, calcium or aluminium lakes. Mention may be made, among water-soluble dyes, of the dyes which are standard in the field under consideration, such as the disodium salt of ponceau, the disodium salt of alizarine, quinoline yellow, the trisodium salt of amaranth, the disodium salt of tartrazine, the monosodium salt of rhodamine, the disodium salt of fuchsine or xanthophyll.
Furthermore, the composition according to the invention can comprise adjuvants commonly used in cosmetic or pharmaceutical compositions intended in particular for a topical application. In particular, these compositions can comprise:
cosmetic and/or pharmaceutical active principles, such as softeners, antioxidants, opacifiers, emollients, hydroxy acids, antifoaming agents, moisturizers, vitamins, fragrances, preservatives, sequestering agents, UV screening agents, ceramides, agents for combating free radicals, bactericides, antidandruff agents, complexing agents, agents for combating hair loss, or antifungal or antiseptic agents;
fillers, pearlescent agents, lakes, thickeners, gelling agents, polymers, in particular fixing or conditioning polymers, propellants, basifying or acidifying agents, or plasticizers;
additional hydrophilic polymers, such as poly(vinyl alcohol)s and their copolymers, polysaccharides or cellulose polymers, or natural proteins or synthetic polypeptides;
film-forming polymers, in particular in aqueous dispersion;
surfactants, in particular anionic or non-ionic surfactants, which are optionally silicone surfactants.
Of course, a person skilled in the art will take care to choose this or these optional adjuvants and/or their amounts so that the advantageous properties of the composition according to the invention are not, or not substantially, detrimentally affected by the envisaged addition.
The compositions according to the invention can be provided in various forms and in particular in the form of oil-in-water, water-in-oil or multiple emulsions; of aqueous or oily dispersions or of dispersions in a solvent medium; of aqueous, aqueous/alcoholic or oily solutions or of solutions in a solvent medium; of aqueous or oily gels; or of microemulsions.
The compositions according to the invention find an application in particular as cosmetic compositions for caring for or making up keratinous fibres, in particular eyelashes and/or hair.
The invention is illustrated in more detail in the following examples.
A/Retraction Measurement Method
The principle includes measuring, before treatment and after treatment, the length of a test specimen of isolated stratum corneum and in determining the percentage of retraction of the test specimen.
Use is made of 1 cmxc3x970.4 cm test specimens of stratum corneum with a thickness ranging from 10 to 20 xcexcm positioned on an MTT 6.0 extensometer sold by the company Diastron.
The test specimen is placed between 2 jaws and then left for 12 hours in an atmosphere at 30xc2x0 C. and 40% relative humidity.
The test specimen is tensioned at the rate of 2 mm/minute by a length of between 5 and 10% of the initial length in order to determine the length L1 from which the test specimen begins to exert a force on the jaws detected by the device.
The test specimen is subsequently relaxed and then 2 mg of an aqueous composition comprising 7% by weight of polymer are applied to the stratum corneum. After complete evaporation of the composition, the test specimen is tensioned under the same conditions as those described above in order to also determine the length L2 for the treated test specimen.
The percentage of retraction is determined by the ratio:
100xc3x97(L2xe2x88x92L1)/L1. 